I. Field of the Invention
The present invention relates to ceramic cutting tools.
II. Description of the Prior Art
There are a number of previously known ceramic cutting tools and most of these cutting tools are based on aluminum oxide as the primary material. Most of these previously known ceramic cutting tools are capable of machining ferrous metals at high speeds only during finishing operations where the feed rate of the tool and the cutting depth is relatively light. This limitation is due primarily to the low thermal shock resistance of these ceramic tools so that the tools crack and chip with higher feed rates and cutting depths.
There have, however, been a number of previously known ceramic cutting tools which have titanium carbide as an additive for the cutting tool. Such cutting tools are known as "black ceramics" due to their color. The black ceramics have better thermal shock resistance than the tools made only from aluminum oxide due to the better thermal conductivity of titanium carbide than aluminum oxide.
While such "black ceramics" are capable of higher tool feed rates than aluminum oxide tools due to their higher thermal conductivity, such "black ceramics" disadvantageously have limited tool life.